The timing of anal fistula surgery is recommended after the internal and external orifices of the fistula and the fistula tract are fully formed. Anal fistula belongs to the localized infectious disease of anal canal, and the cause of its development is related to the irritation and infection of the internal orifice of the anal saphenous fossa. Anal fistula can be diagnosed by anal fingerprinting and perianal ultrasound. Surgical timing, it is recommended to form a fistula and then elective surgery, can effectively clarify the direction of the branches of the fistula tract, and the surgical treatment effect is more thorough. The localized internal opening and the fistula wall are stripped and removed through surgery, and the external opening is treated. After the diagnosis of anal fistula, it is recommended that the patient under the guidance of the doctor according to the condition of the earliest possible operation, to avoid the local inflammatory infection aggravation.